yeah, I've noticed that too. it is the work of pump groups and it is really interesting to see how many newbies are following these pump groups and pour their money in their pockets easily!
it is a nice move for many though, because these nearly dead altcoins have a lot of miners who have billions of these coins in their bags for no reason which they gave up on but now they can dump it to get a nice amount of bitcoin.
Yeah its basically a way to relieve newbies of their coins. The ones who fall for it typically see the prices rising and want to jump on the bandwagon without researching the coin or realizing they are being duped.
When you are bagholding some dead coin of course its always lovely to see it get pumped out of nowhere and is the only reason I backup all my dead alts somewhere if they are not on an exchange already.